Process for the manufacture of a pesticide from petroleum hydrocarbons



United States Patent 3,454,664 PROCESS FOR THE MANUFACTURE OF A PESTI- CllDlE FROM PETROLEUM HYDROCARBONS Salimuzzaman Siddiqui, 243 Issar Dass Road, Garden East, Shabbir A. Qureshi, 113 C, block 2, P.E.C.H. Society, and Shahid H. Ashrafi,B-IV-15/6 Nazimobad, all of Karachi, Pakistan N Drawing. Filed Nov. 18, 1964, Ser. No. 412,245 Int. Cl. C07c 17/10, 17/02 U.S. Cl. 260-660 2 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to the production of a pesticidal composition by subjecting a petroleum hydrocarbon having a boiling range of 35-155 C, to chlorination at a temperature below 30 C. in the presence of water or a 1-4% aqueous solution of sodium or calcium chloride and a hydrocarbon which has been previously chlorinated. The chlorination is continued under such conditions until the specific gravity of the chlorinated product reaches 1.40 to 1.45. Preferably, when the specific gravity reaches 1.30-1.35 the latter is separated from the aqueous phase and the chlorination continued under the same temperature conditions until the specific gravity reaches 1.40-1.45.

This invention relates to a process for the production of a pesticide from petroleum hydrocarbons boiling in the range of 35 C.-155 C., and in particular to a 2- stage chlorination process.

There is a known process for the direct chlorination of large batches of high boiilng petroleum fractions such as kerosene and parafiin wax; however, when fractions having a boiling point range lower than that of kerosene are chlorinated in this manner, the reaction, even with efiicient cooling arrangements, involves the danger of explosions and fires, apparently due to overheating at the point of injection of the chlorine gas.

It is an object of this invention therefore to chlorinate low boiling petroleum fractions under such conditions that the danger of explosions and fire is obviated, and to obtain a pesticide by this reaction.

Upon further study of the specification and claims other objects and advantages of the present invention will become apparent.

To attain these objects according to the present invention, the process for the production of a pesticide from petroleum hydrocarbons boiling in the range of 35-155 C. comprises chlorinating the hydrocarbons at a temperature not exceeding 30 C., in the presence of water and chlorinated petroleum hydrocarbons till the specific gravity of the partially chlorinated product rises to 1.30- 1.35; separating the partly chlorinated product from the aqueous phase; and continuing the chlorination of the resulting product at a temperature not exceeding 30 C. till the specific gravity of the chlorinated product rises to 1.40-1.45. (All specific gravities are measured at 15 C. for the chlorinated hydrocarbon and at 15 C. for water.)

The petroleum hydrocarbons which have been found most suitable are noted below. Two grades of gasoline used in experiments were marketed by Burmah Shell and had the following specification limits and typical test figures:

Amongst the locally produced (Attock 'Oil Company, Rawalpindi) products SBP 60/ 120 has been usedfor preparing this pesticide of our invention. This particular grade has the following characteristics:

(1) Specific gravity-0.728-0.734 g./cc. at 60 F.

(2) Reid vapour pressure8.0 lbs/sq. inch at 100 F.

(3) Sulphur content0.012 percent by weight (4) Colour-Less than 1.0/18 cell (IP) (5) Aromatics12.l7% by volume (7) Paraflfins and naphthenes-85-88% (8) Distillation:

Initial boiling point-35-43 C. 8-12% preferably about 10% at 60 C. -25 preferably about at 60 C. -35% preferably about at 74 C. -45% preferably about at 90 C. -55% preferably about at 98 C. -65% preferably about at 104 C. -75% preferably about at 110 C. -85% preferably about at 120 C. -95% preferably about at 132 C. Final boiling point146-150 C.

In the first step of chlorination, a 1-4% by weight aqueous solution of sodium or calcium chloride can be used instead of water. In any event, the proportion of water or aqueous saline solution is not more than 5 percent, preferably 2-5%.

The chlorinated petroleum hydrocarbons to be used in the process can advantageously be the final chlorinated product itself, prepared in the first instance by carrying out the chlorinaton carefully in small batches. Alternatively, the chlorinated hydrocarbon of 1 to 11 carbon atoms wherein the chlorine content of the molecule is at least 60 percent by weight. The proportion of such chlorinated hydrocarbons can be 10-20% by volume of the petroleum hydrocarbons.

The temperature of chlorination for the chlorination stages is maintained at a level less than 30 C., the preferred temperature range being 1520 C.

The process can be conducted under supra-, subor atmospheric pressure, the preferred pressure being 13.5 to 14.5 lbs./sq. inch (absolute).

The rate of chlorination may be varied, but it is preferred that the initial rate of chlorine introduction in the first stage be maintained for about 2-3 hours, and then gradually increased about 6-8 fold over a period ofabout 3-6 hours. In the second stage of chlorination, the rate is preferably maintained at about 2-4 fold of the initial chlorination rate of the first stage.

For convenience, the final chlorinated product is left standing at room temperature for about an hour, whereby a major portion of the unreacted chlorine is selfpurged. The product, which heats up to about 60 C. in this process of purging, is then scrubbed free of the residual chlorine and hydrochloric acid and dried in vacuo or over anhydrous calcium chloride or sodium sulphate.

The process has been split up into two stages because in the first stage where the specific gravity of the petroleum hydrocarbons rises from 0.7 to 1.3-1.35 g./cc., demands a rigid control both over the chlorination rates as well as the temperature, to avoid explosion and fire.

The addition of the chlorinated hydrocarbons accelerates the absorption of chlorine in the petroleum hydrocarbons even in the absence of sunlight. Direct chlorination, involves the danger of fire which may initiate from the point of injection due to accumulation of heat of reaction. This is avoided by submerging the injection point with sufiicient quantity of aqueous solution (not more than 5%) thus allowing the gas first to pass through the aqueous layer and then on to the supernatant petroleum fraction, for absorption. An additional advantage of the aqueous layer lies in the absorption of the HCl generated in the process of chlorination.

The chlorine content of the product prepared according to this invention is about 60%. Its stability has been tested by keeping it at room temperature (20 C.i4 C.), for an extended period/ The product became light pale in colour but no breakdown of the product was observed.

The product, which has been named Petkolin possesses high toxicity towards some pests and less towards others, as illustrated by the following table.

Lethal dose per insect,

Name of pest Pesticide LD Petkolin microgram 64-06 Cockroaches "(112.1132 inicrogram 823g et olin, mierogram Houseflms "{D.D.T microgram 1. 6

Distillation Percent Range, Distillate No. C. (by Volume) 1 60-95 20-30 percent, preferably about 26%. 2 95-125 25-35 percent, preferably about 26%. 3 125-150 10-15 percent, preferably about 12%. 4 Residue 30-40 percent, preferably about 36%.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore,

to be construed as merely illustrative, and not limitative 4 of the remainder of the specification and claims in any way whatsoever.

EXAMPLE To a vertical chlorination column having a diameter 5 of 5 cm., fitted with a cooling coil, ml. of water is fed which is sufiicient to cover the chlorine injection point. Petroleum hydrocarbons boiling in the range of 40-155 C. (320 ml.) and 80 ml. of previously chlorinated hydrocarbons having a specific gravity of 1.4 are transferred to the column, and the contents are cooled to 15-30 C. The chlorination is carried out first at the rate of about 0.5 liter/minute for a period of 2-3 hours and then gradually increased to 34 liters/minute over a period of 3-6 hours. When the specific gravity of the chlorinated product rises to 1.3 to 1.35, the chlorination is stopped and the mixture allowed to settle. The lower layer comprising the chlorinated petroleum hydrocarbons is transferred to another column for the second stage of chlorination, while the upper aqueous layer of hydrochloric acid (specific gravity 1.18-1.20) is tapped off.

The partly chlorinated petroleum hydrocarbons are further chlorinated at 1530 C. with the chlorine inlet rate of 1-2 liters/minute till the specific gravity of the chlorinated product has risen to 1.45. The product is washed first with water and then with calcium carbonate to remove any unreacted chlorine and hydrochloric acid. It is then dried in vacuo.

The preceding example can be repeated with similar success, but substituting the generic or preferred reactants and operating conditions herein before described. From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adopt it to various usages and conditions. Consequently, such changes and modifications are properly, equitably, and intended to be, within the full range of equivalence of the following claims.

What is claimed is:

1. In a process for the production of pesticides by the chlorination of petroleum hydrocarbon fractions boiling within the range of 35-155 C. until a chlorinated product having a specific gravity of the order of 1.40-1.45 is obtained, the step of producing an initial chlorinated product having a specific gravity of the order of 1.30-1.35 by effecting chlorination of said petroleum hydrocarbon fraction at a temperature of the order of 15-30 C., said hydrocarbon fraction being admixed with 10-20%, by volume, of a chlorinated hydrocarbon having 1-11 carbon atoms and containing at least 60%, by weight of chlorine and with an aqueous phase selected from the group consisting of water, a 1-4%, by weight, of aqueous solution of sodium chloride, and 1-4%, by weight, of aqueous solution of calcium chloride, said chlorination be continued until the specific gravity of the chlorinated hydrocarbon is of the order of 1.30-1.35.

2. Process according to claim 1 wherein after the initial 2-3 hours of chlorination the rate of chlorine addition is gradually increased by about 6-8 fold.

BERNARD HELFIN, Primary Examiner.

H. T. MARS, Assistant Examiner.

U.S. Cl. X.R. 

